Method for collaborative control of organic nitrogen and inorganic nitrogen in denitrification process

ABSTRACT

A method for collaborative optimization control method for organic nitrogen and inorganic nitrogen in a denitrification process is provided. The method includes: establishing ASM-mDON-DIN models for simultaneous simulation of microbial dissolved organic nitrogen (mDON) and inorganic nitrogen (DIN) in denitrification processes; and selecting a corresponding ASM-mDON-DIN model according to a set carbon/nitrogen ratio to collaboratively optimize the concentration values of mDON and DIN in the effluent in the denitrification process, to obtain best process operation parameter values.

CROSS-REFERENCE TO RELAYED APPLICATIONS

Pursuant to 35 U.S.C. § 119 and the Paris Convention Treaty, thisapplication claims foreign priority to Chinese Patent Application No.202111652401.1 filed Dec. 30, 2021, the contents of which, including anyintervening amendments thereto, are incorporated herein by reference.Inquiries from the public to applicants or assignees concerning thisdocument or the related applications should be directed to: MatthiasScholl P.C., Attn.: Dr. Matthias Scholl Esq., 245 First Street, 18thFloor, Cambridge, Mass. 02142.

BACKGROUND

The disclosure relates to the field of wastewater treatment, and moreparticularly to a method for collaborative control of organic nitrogenand inorganic nitrogen in a denitrification process.

The total dissolved nitrogen in sewage includes inorganic nitrogen (DIN)and dissolved organic nitrogen (DON). In many areas, a high standard isrequired for the discharge threshold of total nitrogen (TN) in theeffluent from municipal sewage treatment plants, so as to control theeutrophication and anoxia of the received water body. For this standard,some sewage plants adopt post denitrification or other processes toimprove the denitrification efficiency. When the concentration of thetotal nitrogen is low (<10 mg/L), 20% to 40% of the total nitrogen inthe effluent from the sewage treatment plant exists in the form of DON.Therefore, the DON in the effluent is one of key factors to limit thelower concentration of total nitrogen in the effluent from the sewagetreatment plant. The total nitrogen in the effluent from the sewageplant is affected by the removal rage of DIN and is also directlyrelated to the concentration of DON. Therefore, in order to realize thestandard discharge of total nitrogen in the effluent from the sewageplant under high standards, it is necessary to collaboratively controlorganic nitrogen and inorganic nitrogen.

At present, the researches on the control of total nitrogen in theeffluent mainly focus on the simulation and optimization control oforganic nitrogen, but do not focus on the collaborative control ofinorganic nitrogen and organic nitrogen. The International WaterAssociation (IWA) has been committed to the construction and practice ofthe mathematical denitrification model for activated sludge in sewagetreatment for a long term. The IWA pays more attention to thetransformation kinetic parameters of inorganic nitrogen and the nitrogenbalance in wastewater biological treatment systems. For example, theactivated sludge nitrogen model issued in 2008 by the IWA described thetransformation and removal of DIN components (ammonia nitrogen, nitratenitrogen and nitrite nitrogen) during the complete denitrificationprocess of the activated sludge but did not consider microbial dissolvedorganic nitrogen (mDON) produced by microbial metabolism in thedenitrification effluent, so the DIN and DON in the effluent could notbe simulated simultaneously.

SUMMARY

An objective of the disclosure is to solve the problem that the totalnitrogen in the effluent from a sewage plant is difficult to satisfy thestandard discharge under high standards. Based on the activated sludgedenitrification model of the IWA, a transformation mathematical modelfor simultaneous simulation of DON and DIN in a sewage biologicaltreatment system is firstly constructed to realize the simultaneoussimulation and collaborative operation control of DON and DIN in theeffluent from a sewage plant, so that a new method is provided tosatisfy the standard discharge of total nitrogen in the sewage plantunder high standards.

A method for collaborative optimization control method for organicnitrogen and inorganic nitrogen in a denitrification process isprovided, the method comprising:

S1: establishing ASM-mDON-DIN models for simultaneous simulation ofmicrobial dissolved organic nitrogen (mDON) and inorganic nitrogen (DIN)in denitrification processes; and

S2: selecting a corresponding ASM-mDON-DIN model according to a setcarbon/nitrogen ratio to collaboratively optimize the concentrationvalues of mDON and DIN in the effluent in the denitrification process,to obtain best process operation parameter values.

In a class of this embodiment, in S1, operations for establishing theASM-mDON-DIN models comprise:

S1-1: data collection: measuring the chemical oxygen demand (COD), totalnitrogen (TN), inorganic nitrogen (iDIN), dissolved organic nitrogen(rDON) and pH in the influent of a target sewage plant in thedenitrification process, the inorganic nitrogen (eDIN) and dissolvedorganic nitrogen (eDON) in the effluent, dissolved oxygen (DO), thehydraulic retention time (t) of the denitrification stage, and the mixedliquor suspended solid (MLSS) of activated sludge;

S1-2: model construction: according to the kinetic process ofproduction, transformation and consumption of mDON during the completedenitrification process, adding mDON as a new component and thecarbon/nitrogen ratio as a new parameter into the ASM model, andconstructing ASM-mDON-DIN models 1 and 2 at different carbon/nitrogenratios by using mDON and DIN as objects;

S1-3: model initialization: initializing the models based on the datacollected in S1-1, the measured values of model parameters and theASM-mDON-DIN models constructed in S1-2;

S1-4: model calibration: calibrating the parameter estimation functionbased on the simulated mDON and DIN kinetics and the result ofsensitivity analysis; and

S1-5: model establishment: replacing the initial parameter values in themodels with the parameter calibration values to obtain calibratedASM-mDON-DIN models 1 and 2.

In a class of this embodiment, in S3, operations for selectingcollaborative optimization parameters comprise:

S2-1: setting process parameter values: determining the set values ofcarbon/nitrogen ratio, pH and dissolved oxygen;

S2-2: model selection: selecting the ASM-mDON-DIN model 1 or 2 accordingto the numerical value of the carbon/nitrogen ratio in S2-1;

S2-3: collaborative optimization: based on the model selected in S2-2,obtaining the minimum value of the sum of the concentration of organicnitrogen and the concentration of inorganic nitrogen in the effluent andcorresponding process operation parameters by using the processparameter values set in S2-1 as a design factor of the response surfacemethodology and the sum of the concentration of organic nitrogen and theconcentration of inorganic nitrogen in the effluent as a response value;and

S2-4: outputting best parameter values: outputting the minimum value ofthe sum of the concentration of inorganic nitrogen and the concentrationof organic nitrogen in the effluent and the corresponding processoperation parameters, i.e., carbon/nitrogen ratio, pH and dissolvedoxygen, obtained in S2-3.

In a class of this embodiment, the measured values of model parameterscomprise the initial values of the yield coefficient (Y_(H)) of anoxicgrowth of heterotrophic bacteria measured based on the data collected inS1-1, the proportion (f_(H,DON)) of mDON formed by heterotrophicbacteria based on organism growth, the ammoniated mDON half-saturationconstant (K_(H,DON)) of heterotrophic bacteria, the maximum specificgrowth rate (μ_(H)) of heterotrophic bacteria and the nitratehalf-saturation constant (K_(NO) ₃ ) of heterotrophic bacteria.

In a class of this embodiment, the inorganic nitrogen component S_(DIN)comprises ammonia nitrogen, nitrate nitrogen and nitrite nitrogen.

In a class of this embodiment, the ASM-mDON-DIN model 1 comprises 10components, 8 processes, 22 parameters and a kinetic parameter, i.e.,the inhibition constant (K_(I4S) _(s) ) of the anoxic substrate ofheterotrophic bacteria; and, the ASM-mDON-DIN model 2 comprises 10components, 8 processes and 22 parameters:

10 components: heterotrophic bacteria X_(H), particulate inert substanceXi, dissolved biodegradable organic matter S_(S), microbial organicnitrogen S_(mDON), ammonia nitrogen S_(NH), nitrate nitrogen S_(NO3),nitrite nitrogen S_(NO2), nitric oxide S_(NO), nitrous oxide S_(N2O) andalkalinity S_(ALK);

8 processes: four-step anoxic growth of heterotrophic bacteria based onthe dissolved biodegradable organic matter, comprising conversion ofnitrate nitrogen into nitrite nitrogen, conversion of nitrite nitrogeninto nitric oxide, conversion of nitric oxide into nitrous oxide andconversion of nitrous oxide into nitrogen, and decay of heterotrophicbacteria, ammonification of microbial dissolved organic nitrogen,assimilative reduction of nitrate nitrogen into nitrite nitrogen andassimilative reduction of nitrite nitrogen into ammonia nitrogen; and

22 parameters: the yield coefficient Y_(H) of anoxic S_(s)-based growthof heterotrophic bacteria, the oxygen containing proportion i_(XB) oforganism, the proportion f_(H,DON) of mDON formed by heterotrophicbacteria based on organism growth, the proportion f_(I) of inertsubstances produced by organism, the maximum specific growth rate μ_(H)of anoxic growth of heterotrophic bacteria, the half-saturationutilization constant K_(s) of the substrate of heterotrophic bacteria,the ammonia half-saturation constant K_(H,NH) of heterotrophic bacteria,the anoxic growth factor η₂ of heterotrophic bacteria in the process 2,the anoxic growth factor η₃ of heterotrophic bacteria in the process 3,the anoxic growth factor η₄ of heterotrophic bacteria in the process 4,the nitrate nitrogen half-saturation constant K_(NO) ₃ , the nitritenitrogen half-saturation constant K_(NO) ₂ , the nitric oxidehalf-saturation constant K_(NO), the nitrous oxide half-saturationconstant K_(N) ₂ _(O), the decay coefficient b_(H) of heterotrophicbacteria, the ammoniated mDON half-saturation constant K_(H,DON) ofheterotrophic bacteria, the ammonification rate κ_(α) of microbialdissolved organic nitrogen, the NO₃ ⁻—N half-saturation constantK_(7,NO3) of ANRA, the inhibition constant K_(I7NH) of ammonia nitrogenin the ANRA process, the inhibition constant K_(I8NO2) of nitritenitrogen in the ANRA process, the half-saturation constant K_(8,NO2) ofnitrite nitrogen in the ANRA process and the oxygen half-saturationconstant K_(H,O) of heterotrophic bacteria.

In a class of this embodiment, the ASMN-mDON-DIN models 1 and 2 aredivided according to the carbon/nitrogen ratio in the influent:

(1) when the carbon/nitrogen ratio is less than or equal to 4, the model1 is selected, and the kinetic equations for the model 1 are as follows:

${{{DIN}\left( S_{DIN} \right)}:\frac{{dS}_{DIN}}{dt}} = {{\left( {{- i_{XB}} - \frac{f_{H,{DON}}}{Y_{H}}} \right)\left( {V_{1} + V_{2} + V_{3} + V_{4}} \right)} + V_{6} + \left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} +} \right.}$${\left. \frac{1}{0.571} \right)V_{2}};$${{{{mDON}\left( S_{mDON} \right)}:\frac{{dS}_{mDON}}{dt}} = {{\frac{f_{H,{DON}}}{Y_{H}}\left( {V_{1} + V_{2} + V_{3} + V_{4}} \right)} - V_{6}}};$${{{heterotrophic}{{bacteria}\left( X_{H} \right)}:\frac{{dX}_{H}}{dt}} = {V_{1} + V_{2} + V_{3} + V_{4} - V_{5}}};$${{{particulate}{inert}{{substance}\left( X_{I} \right)}:\frac{{dX}_{I}}{dt}} = {f_{I}V_{5}}};$${{dissolved}{biodegradable}{organic}{{matter}\left( S_{S} \right)}:\frac{{dS}_{s}}{dt}} = {{- \frac{1}{Y_{H}}}\left( {V_{1} + V_{2} + V_{3} +} \right.}$V₄) − 1.14V₇ − 3.43V₈;${{{nitric}{{oxide}\left( S_{NO} \right)}:\frac{{dS}_{NO}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{2}} + {\left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} + \frac{1}{0.571}} \right)V_{3}}}};$${{{nitrous}{{oxide}\left( S_{N2O} \right)}:\frac{{dS}_{N2O}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{3}} + {\left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} + \frac{1}{0.571}} \right)V_{4}}}};$${{{alkalinity}\left( S_{ALK} \right)}:\frac{{dS}_{ALK}}{dt}} = {{\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{1}} - \left( {\frac{i_{XB}}{14} + \frac{f_{H,{DON}}}{14Y_{H}} -} \right.}$${{\left. \frac{1 + {2.86f_{H,{DON}}} - Y_{H}}{14 \cdot \left( {0.571Y_{H}} \right)} \right)V_{2}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{3}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{4}} + {\frac{1}{14}V_{6}} + {\frac{1}{7}V_{8}}};$

(2) when the carbon/nitrogen ratio is greater than 4, the model 2 isselected, and the kinetic equations for the model 2 are as follows:

${{{DIN}\left( S_{DIN} \right)}:\frac{{dS}_{DIN}}{dt}} = {{\left( {{- i_{XB}} - \frac{f_{H,{DON}}}{Y_{H}}} \right)\left( {V_{1} + V_{2}^{\prime} + V_{3} + V_{4}^{\prime}} \right)} + V_{6} + \left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} +} \right.}$${\left. \frac{1}{0.571} \right)V_{2}^{\prime}};$${{{{mDON}\left( S_{mDON} \right)}:\frac{{dS}_{mDON}}{dt}} = {{\frac{f_{H,{DON}}}{Y_{H}}\left( {V_{1} + V_{2}^{\prime} + V_{3} + V_{4}^{\prime}} \right)} - V_{6}}};$${{{heterotrophic}{{bacteria}\left( X_{H} \right)}:\frac{{dX}_{H}}{dt}} = {V_{1} + V_{2}^{\prime} + V_{3} + V_{4}^{\prime} - V_{5}}};$${{{particulate}{inert}{{substance}\left( X_{I} \right)}:\frac{{dX}_{I}}{dt}} = {f_{I}V_{5}}};$${{dissolved}{biodegradable}{organic}{{matter}\left( S_{S} \right)}:\frac{{dS}_{s}}{dt}} = {{- \frac{1}{Y_{H}}}\left( {V_{1} + V_{2}^{\prime} + V_{3} +} \right.}$V₄^(′)) − 1.14V₇ − 3.43V₈;${{{nitric}{{oxide}\left( S_{NO} \right)}:\frac{{dS}_{NO}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{2}^{\prime}} + {\left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} + \frac{1}{0.571}} \right)V_{3}}}};$${{nitrous}{{oxide}\left( S_{N2O} \right)}:\frac{{dS}_{N2O}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{3}} + \left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} +} \right.}$${\left. \frac{1}{0.571} \right)V_{4}^{\prime}};$${{{alkalinity}\left( S_{ALK} \right)}:\frac{{dS}_{ALK}}{dt}} = {{\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{1}} - \left( {\frac{i_{XB}}{14} + \frac{f_{H,{DON}}}{14Y_{H}} -} \right.}$${\left. \frac{1 + {2.86f_{H,{DON}}} - Y_{H}}{14 \cdot \left( {0.571Y_{H}} \right)} \right)V_{2}^{\prime}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{3}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{4}^{\prime}} + {\frac{1}{14}V_{6}} + {\frac{1}{7}{V_{8}.}}$

In a class of this embodiment, the ASMN-mDON-DIN models 1 and 2 comprise8 process rate expressions respectively, i.e., V₁-V₈ and V₁′-V₈′:

(1) the anoxic growths (V₁ and V₁′) of heterotrophic bacteria based ondissolved biodegradable organic matters (Ss) are:

V ₁=μ_(H) ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO) ₃ (t)·M_(H,O)(t)

V ₁ ′=V ₁

(2) the anoxic growths (V₂ and V₂′) of heterotrophic bacteria based ondissolved biodegradable organic matters are:

V ₂=μ_(H)·η₂ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO) ₂ (t)·M_(H,O)(t)

V ₂′=α·μ_(H)·η₂ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO) ₂(t)·M _(H,O)(t)

(3) the anoxic growths (V₃ and V₃′) of heterotrophic bacteria based ondissolved biodegradable organic matters are:

V ₃=μ_(H)·η₃ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO)(t)·M_(H,O)(t)

V ₃ ′=V ₃

(4) the anoxic growths (V₄ and V₄′) of heterotrophic bacteria based ondissolved biodegradable organic matters are:

V ₄=μ_(H)·η₄ ·X _(H)(t)·M _(H,I,S) _(s) (t)·M _(H,NH)(t)·M _(H,N) ₂_(O)(t)·M _(H,O)(t)

V ₄′=α·μ_(H)·η₄ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,N) ₂_(O)(t)·M _(H,O)(t)

(5) the decays (V₅ and V₅′) of heterotrophic bacteria are:

V ₅ =b _(H) ·M _(H,NO) ₃ (t)·X _(H)(t)

V ₅ ′=V ₅

(6) the ammonification (V₆ and V₆′) of microbial dissolved organicnitrogen is:

V ₆=κ_(α) ·X _(H)(t)·M _(H,mDON)(t)

V ₆ ′=V ₆

(7) the assimilative reduction (V₇ and V₇′) of nitrate into nitrite is:

V ₇=1.2·i _(XB) ·M _(ANRA,NO) ₃ (t)·M _(I,NH)(t)·M _(I7,NO) ₂ (t)(V ₁ +V₂ +V ₃ +V ₄ −V ₆)

V ₇ ′=V ₇

(8) the assimilative reduction (V₈ and V₈′) of nitrite into ammonianitrogen is:

V ₈=1.2·i _(XB) ·M _(ANRA,NO) ₂ (t)·M _(I,NH)(t)(V ₁ +V ₂ +V ₃ +V ₄ −V₆)

V ₈ ′=V ₈

where M_(H,S) _(s) (t) is the Monod item of the substrate limit usingthe dissolved biodegradable organic matters of heterotrophic bacteria;M_(H,I,S) _(s) (t) is the inhibition Monod item of the dissolvedbiodegradable organic matters of heterotrophic bacteria; M_(H,NH)(t) isthe Monod item of the substrate limit using ammonia nitrogen; M_(H,O)(t)is the Monod item of the oxygen limit of heterotrophic bacteria;M_(H,NO) ₃ (t) is the Monod item of the nitrate nitrogen limit; M_(H,NO)₂ (t) is the Monod item of the nitrite nitrogen limit; M_(H,NO)(t) isthe Monod item of the nitric oxide limit; M_(H,N) ₂ _(O)(t) is the Monoditem of the nitrous oxide limit; M_(ANRA,NO) ₃ (t) is the Monod item ofthe nitrate nitrogen limit during the assimilative reduction of nitrateinto nitrite nitrogen; M_(I,NH)(t) is the inhibition Monod item ofammonia nitrogen during the assimilative reduction of nitrate intonitrite nitrogen; M_(I7,NO) ₂ (t) is the inhibition Monod item ofnitrite during the assimilative reduction of nitrate into nitritenitrogen; M_(ANRA,NO) ₂ (t) is the Monod item of the nitrite limitduring the assimilative reduction of nitrite nitrogen into ammonianitrogen; and, M_(H,mDON)(t) is the Monod item of the mDON limitproduced by heterotrophic bacteria.

In a class of this embodiment, the sensitivity analysis uses anabsolute-relative sensitivity equation to calculate the influences ofparameter changes on mDON and DIN.

Preferably, except for five model parameter values to be measured, theinitial values of the common chemometric coefficients and kineticparameters of the ASM-mDON-DIN models 1 and 2 are shown in Table 1below.

TABLE 1 Initial values of common chemometric coefficients and kineticparameters of the ASM-mDON-DIN models 1 and 2 Parameter Unit Numericalvalue Chemometric coefficients i_(XB) mg (N)/mg (COD_(XH)) 0.086 f₁ mg(COD_(XI))/mg (COD_(XH)) 0.2 Kinetic parameters K_(s) mg (COD)/L 20N_(H, NH) mg (NH₃-N)/L 0.05 K_(H, O) mgO₂/L 0.2 n₂ — 0.57 n₃ — 1.25 n₄ —1.25 K_(NO) ₂ mg N/L 0.15 K_(I4S) _(s) mg (COD)/L 120 K_(NO) mg N/L0.0003 K_(N) ₂ _(O) mg N/L 1.1 b_(H) mg (COD)/L 0.62 K_(7, NO3) mg N/L0.1 K_(INH) mg N/L 0.05 K_(8, NO2) mg N/L 0.1 k_(a) L/(mg (N) · d) 0.010K_(I8NO2) mg N/L 0.05 K_(I4S) _(s) mg (COD)/L 120

Preferably, the Gujer matrix of the ASM-mDON-DIN models 1 and 2 is shownby Table 2:

TABLE 2 Gujer Matrix of the ASMN-DIN-mDON models 1 and 2 S_(S) S_(H) X₁S_(mDON) S_(NH) S_(NO3) S_(NO2) S_(NO) S_(N2O) S_(ALK) V₁$- \frac{1}{Y_{H}}$ 1 $\frac{f_{H,{DON}}}{Y_{H}}$ $\begin{matrix}{{- i_{XB}} -} \\\frac{f_{H,{DON}}}{Y_{H}}\end{matrix}$ $\begin{matrix}{{- \frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{1.14Y_{H}}} +} \\\frac{1}{1.14}\end{matrix}$ $\begin{matrix}{\frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{1.14Y_{H}} -} \\\frac{1}{1.14}\end{matrix}$ $\begin{matrix}{{- \frac{i_{XB}}{14}} -} \\\frac{f_{H,{DON}}}{14Y_{H}}\end{matrix}$ V₂ $- \frac{1}{Y_{H}}$ 1 $\frac{f_{H,{DON}}}{Y_{H}}$$\begin{matrix}{{- i_{XB}} -} \\\frac{f_{H,{DON}}}{Y_{H}}\end{matrix}$ $\begin{matrix}{{- \frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{0.571Y_{H}}} +} \\\frac{1}{0.571}\end{matrix}$ $\begin{matrix}{\frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{1.14Y_{H}} -} \\\frac{1}{1.14}\end{matrix}$ $\begin{matrix}{{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}} +} \\\frac{\begin{matrix}{1 +} \\{{2.86f_{H,{DON}}} -} \\Y_{H}\end{matrix}}{14 \cdot \left( {0.571Y_{H}} \right)}\end{matrix}$ V₃ $- \frac{1}{Y_{H}}$ 1 $\frac{f_{H,{DON}}}{Y_{H}}$$\begin{matrix}{{- i_{XB}} -} \\\frac{f_{H,{DON}}}{Y_{H}}\end{matrix}$ $\begin{matrix}{{- \frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{0.571Y_{H}}} +} \\\frac{1}{0.571}\end{matrix}$ $\begin{matrix}{\frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{1.14Y_{H}} -} \\\frac{1}{1.14}\end{matrix}$ $\begin{matrix}{{- \frac{i_{XB}}{14}} -} \\\frac{f_{H,{DON}}}{14Y_{H}}\end{matrix}$ V₄ $- \frac{1}{Y_{H}}$ 1 $\frac{f_{H,{DON}}}{Y_{H}}$$\begin{matrix}{{- i_{XB}} -} \\\frac{f_{H,{DON}}}{Y_{H}}\end{matrix}$ $\begin{matrix}{{- \frac{\begin{matrix}{1 +} \\{2.86f_{H,{DON}}}\end{matrix}}{0.571Y_{H}}} +} \\\frac{1}{0.571}\end{matrix}$ $\begin{matrix}{{- \frac{i_{XB}}{14}} -} \\\frac{f_{H,{DON}}}{14Y_{H}}\end{matrix}$ V₅ −1 f₁ V₆ −1 1 $\frac{1}{14}$ V₇ −1.14 −1 1 V₈ −3.43 1−1 $\frac{1}{7}$

In a class of this embodiment, the influent of the denitrificationprocess in the target sewage plant should satisfy the followingconditions: 15° C.<environmental temperature<25° C., 2000 mg/L<sludgeconcentration<5000 mg/L, 10 d<sludge age<30 d, 0<carbon/nitrogenratio≤6.5, 6.5<pH≤8.5, and 0≤dissolved oxygen≤0.5.

Compared with the prior art, the following advantages are associatedwith the method for collaborative control of organic nitrogen andinorganic nitrogen in a denitrification process of the disclosure:

(1) The ASMN-mDON-DIN models established in the disclosure can realizethe simultaneous simulation and collaborative operation control of mDONand DIN, so that a new method is provided to satisfy the standarddischarge of total nitrogen in the sewage plant under high standards.

(2) The ASMN-mDON-DIN models established in the disclosure are high inaccuracy, and the degree of fitting R² between the simulated value andthe measured value is greater than or equal to 0.9 (p<0.05).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a graph of the sum of the concentration of mDON and theconcentration of DIN and the carbon/nitrogen ratio (C/N);

FIG. 1B is a graph of the sum of the concentration of mDON and theconcentration of DIN and the pH; and

FIG. 1C is a graph of the sum of the concentration of mDON and theconcentration of DIN and the dissolved oxygen (DO).

DETAILED DESCRIPTION

The post denitrification process stage of a certain municipal sewagetreatment plant was selected for collaborative optimization control oforganic nitrogen and inorganic nitrogen, where the chemical oxygendemand (COD), total nitrogen (TN), inorganic nitrogen (dDIN), organicnitrogen (rDON) and pH of the influent were 46.33 mg/L, 18.465 mg/L,16.98 mg/L, 1.48 mg/L and 6.53, respectively; the organic nitrogen(eDIN) and organic nitrogen (eDON) of the effluent were 11.97 mg/L and2.26 mg/L, respectively; and, in the process operation parameters, thedissolved oxygen (DO) was 0.1 mg/L, the hydraulic retention time (t) ofdenitrification was 140 min, and the mixed liquor suspended solid (MLSS)of the activated sludge was 2600 mg/L. The specific evaluation stepswere described below.

S1: ASM-mDON-DIN models for simultaneous prediction of microbialdissolved organic nitrogen (mDON) and inorganic nitrogen (DIN) indenitrification processes were established.

S1-1: The measurement results of model parameters were calculatedaccording to the collected data: Y_(H)=0.58, f_(H,DON)=0.068,μ_(H)=0.35, K_(NO) ₃ =0.12, K_(H,mDON)=1.55. The initial values of theremaining kinetic and chemometric parameters were shown in Table 1.

S1-2: According to the dynamic process of production, transformation andconsumption of mDON during the complete denitrification process, mDON asa new component and the carbon/nitrogen ratio as a new condition wereadded into the ASM model, and ASM-mDON-DIN models 1 and 2 at differentcarbon/nitrogen ratios were constructed by using mDON and DIN asobjects.

S1-3: Model initialization was performed on the ASM-mDON-DIN models 1and 2.

S1-4: The influences of parameter changes on mDON and DIN werecalculated by using an absolute-relative sensitivity equation aftermodel initialization, and the parameter estimation function wascalibrated based on the initially simulated mDON and DIN concentrationsand the result of sensitivity analysis. The calibrated values of themodels were shown in Table 3.

TABLE 3 Calibrated values of the ASMN-mDON-DIN models Parameter UnitNumerical value Chemometric coefficient Y_(H) mg(COD_(XH))/mg(N) 0.591f_(H, DON) mg(N)/mg(COD_(XH)) 0.081 Kinetic parameter μ_(H) 1/h 0.296K_(NO) ₃ mg (N)/L 0.098 K_(H, mDON) mg (N)/L 2.08 K_(I4S) _(s) mg(COD)/L 117

S1-5: The initial values of parameters in the models were replaced withthe calibrated parameter values to obtain the rate equation of eachcomponent in the models 1 and 2:

Model 1:

${S_{DIN}:\frac{{dS}_{DIN}}{dt}} = {- 0.22\left( {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} +} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, I, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t)) + 0.01 ⋅ X_(H)(t) ⋅ M_(H, mDON)(t) − 0.03 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, NO₂)(t) ⋅ M_(H, O)(t)${S_{mDON}:\frac{{dS}_{mDON}}{dt}} = {0.14\left( {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} +} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, I, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t) + 0.17 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t)⋅M_(H, O)(t)) − 0.01 ⋅ X_(H)(t) ⋅ M_(H, mDON)(t)${X_{H}:\frac{{dX}_{H}}{dt}} = {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} + {0.37 \cdot {X_{H}(t)} \cdot}}$M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, I, S_(s))(t) ⋅ M_(H, NH)(t)⋅M_(H, N₂O)(t) ⋅ M_(H, O)(t) + 0.17 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t) ⋅ M_(H, O)(t)−0.62 ⋅ M_(H, NO₃)(t) ⋅ X_(H)(t)${X_{I}:\frac{{dX}_{I}}{dt}} = {0.124 \cdot {M_{H,{NO}_{3}}(t)} \cdot {X_{H}(t)}}$${S_{S}:\frac{{dS}_{s}}{dt}} = {- 1.69\left( {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} +} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, I, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t) + 0.17 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t)⋅M_(H, O)(t)) − 0.114 ⋅ M_(ANRA, NO₃)(t) ⋅ M_(I, NH)(t) ⋅ M_(I7, NO₂)(t)(V₁ + V₂ + V₃ + V₄ − V₆) − 0.343⋅M_(ANRA, NO₂)(t) ⋅ M_(I, NH)(t)(V₁ + V₂ + V₃ + V₄ − V₆)${S_{NO}:\frac{{dS}_{NO}}{dt}} = {1.9\left( {{0.17 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{2}}(t)} \cdot {M_{H,O}(t)}} -} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t))${S_{N2O}:\frac{{dS}_{N2O}}{dt}} = {1.9\left( {{0.37 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}}(t)} \cdot {M_{H,O}(t)}} -} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, I, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t))${S_{ALK}:\frac{{dS}_{ALK}}{dt}} = {{- {0.005 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}}} -}$0.02 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t) ⋅ M_(H, O)(t) − 0.006 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) − 0.006 ⋅ X_(H)(t) ⋅ M_(H, I, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, N₂O)(t)⋅M_(H, O)(t) + 0.07 ⋅ κ_(a) ⋅ X_(H)(t) ⋅ M_(H, mDON)(t) + 0.141.2 ⋅ i_(XB) ⋅ M_(ANRA, NO₂)(t) ⋅ M_(I, NH)(t)(V₁+V₂ + V₃ + V₄ − V₆)

Model 2:

${S_{DIN}:\frac{{dS}_{mDON}}{dt}} = {- 0.22\left( {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} +} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t)) + 0.01 ⋅ X_(H)(t) ⋅ M_(H, mDON)(t) − 0.048 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, NO₂)(t) ⋅ M_(H, O)(t)${S_{Mdon}:\frac{{dS}_{mDON}}{dt}} = {0.14\left( {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} +} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t)) + 0.3 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t)⋅M_(H, O)(t)) − 0.01 ⋅ X_(H)(t) ⋅ M_(H, mDON)(t)${X_{H}:\frac{{dX}_{H}}{dt}} = {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} + {0.37 \cdot {X_{H}(t)} \cdot}}$M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, N₂O)(t)⋅M_(H, O)(t)) + 0.3 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t) ⋅ M_(H, O)(t) − 0.62 ⋅ M_(H, NO₃)(t)⋅X_(H)(t)${X_{I}:\frac{{dX}_{I}}{dt}} = {0.124 \cdot {M_{H,{NO}_{3}}(t)} \cdot {X_{H}(t)}}$${S_{S}:\frac{{dS}_{s}}{dt}} = {- 1.69\left( {{0.296 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}} +} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) + 0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t)) + 0.3 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t)⋅M_(H, O)(t)) − 0.114 ⋅ M_(ANRA, NO₃)(t) ⋅ M_(I, NH)(t) ⋅ M_(I7, NO₂)(t)(V₁ + V₂ + V₃ + V₄ − V₆)−0.343 ⋅ M_(ANRA, NO₂)(t) ⋅ M_(I, NH)(t)(V₁ + V₂ + V₃ + V₄ − V₆)${S_{NO}:\frac{{dS}_{NO}}{dt}} = {1.9 \cdot \left( {{0.3 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{2}}(t)} \cdot {M_{H,O}(t)}} -} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t))${S_{N2O}:\frac{{dS}_{N2O}}{dt}} = {1.9 \cdot \left( {{0.37 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}}(t)} \cdot {M_{H,O}(t)}} -} \right.}$0.37 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, N₂O)(t) ⋅ M_(H, O)(t))${S_{ALK}:\frac{{dS}_{ALK}}{dt}} = {{- {0.005 \cdot {X_{H}(t)} \cdot {M_{H,S_{s}}(t)} \cdot {M_{H,{NH}}(t)} \cdot {M_{H,{NO}_{3}}(t)} \cdot {M_{H,O}(t)}}} -}$0.036 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, NO₂)(t) ⋅ M_(H, O)(t) − 0.006 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t)⋅M_(H, NH)(t) ⋅ M_(H, NO)(t) ⋅ M_(H, O)(t) − 0.006 ⋅ X_(H)(t) ⋅ M_(H, S_(s))(t) ⋅ M_(H, NH)(t) ⋅ M_(H, N₂O)(t)⋅M_(H, O)(t) + 0.007 ⋅ X_(H)(t) ⋅ M_(H, mDON)(t) + 0.014 ⋅ M_(ANRA, NO₂)(t) ⋅ M_(I, NH)(t)(V₁ + V₂ + V₃+V₄ − V₆);

where M_(H,S) _(s) (t) was the Monod item of the substrate limit usingthe dissolved biodegradable organic matters of heterotrophic bacteria;M_(H,I,S) _(s) (t) was the inhibition Monod item of the dissolvedbiodegradable organic matters of heterotrophic bacteria; M_(H,NH)(t) wasthe Monod item of the substrate limit using ammonia nitrogen; M_(H,O)(t)was the Monod item of the oxygen limit of heterotrophic bacteria;M_(H,NO) ₃ (t) was the Monod item of the nitrate nitrogen limit;M_(H,NO) ₂ (t) was the Monod item of the nitrite nitrogen limit;M_(H,NO)(t) was the Monod item of the nitric oxide limit; M_(H,N) ₂_(O)(t) was the Monod item of the nitrous oxide limit; M_(ANRA,NO) ₃ (t)was the Monod item of the nitrate nitrogen limit during the assimilativereduction of nitrate into nitrite nitrogen; M_(I,NH)(t) was theinhibition Monod item of ammonia nitrogen during the assimilativereduction of nitrate into nitrite nitrogen; M_(I7,NO) ₂ (t) was theinhibition Monod item of nitrite during the assimilative reduction ofnitrate into nitrite nitrogen; M_(ANRA,NO) ₂ (t) was the Monod item ofthe nitrite limit during the assimilative reduction of nitrite nitrogeninto ammonia nitrogen; and, M_(H,mDON)(t) was the Monod item of the mDONlimit produced by heterotrophic bacteria.

The degree of fitting between the calibrated simulated value and themeasurement value of mDON and DIN in the effluent was 0.937 (p<0.05) and0.901 (p<0.05), respectively, indicating that the accuracy of modelsimulation was high and the models had been established.

S2: According to the carbon/nitrogen ratio, the ASM-mDON-DIN models ofdifferent kinetic equations were selected for collaborative optimizationof mDON and DIN in the effluent in the denitrification process to obtainbest parameter values, specifically comprising the following steps.

According to the central composite design rule, the value of the processoperation parameter carbon/nitrogen ratio was set as 2.5, 4.5 and 6.5,the value of pH was set as 6.5, 7.5 and 8.5, and the value of DO was setas 0 mg/L, 0.25 mg/L and 0.5 mg/L.

When the value of the carbon/nitrogen ratio was 2.5, the model 1 wasselected; and, when the value of the carbon/nitrogen ratio was 4.5 and6.5, the model 2 was selected.

By using the carbon/nitrogen ratio, pH and DO in the process operationparameter values as design factors of the response surface methodologyand the sum of the concentration of mDON and the concentration of DIN inthe effluent as a response value (See FIGS. 1A-1C), the predicted valueof the sum of the concentration of mDON and the concentration of DIN wasshown in Table 4:

TABLE 4 Predicted value of the sum of the concentration of mDON and theconcentration of DIN in the effluent under different process parametersC/N pH DO (mg/L) mDON + DIN (mg/L) 2.50 6.50 0.00 10.58 6.50 6.50 0.006.04 2.50 6.50 1.00 18.56 6.50 6.50 1.00 13.37 4.50 7.50 0.50 10.24 2.508.50 0.00 10.66 6.50 8.50 0.00 6.40 2.50 8.50 1.00 17.62 6.50 8.50 1.0014.32

The minimum value of the sum of the concentration of mDON and theconcentration of DIN in the effluent and the corresponding processoperation parameters were obtained. When the minimum value of the sum ofthe concentration of mDON and the concentration of DIN was 5.56 mg/L,the carbon/nitrogen ratio was 5.65, pH was 6.74, and DO was 0.30 mg/L.

It will be obvious to those skilled in the art that changes andmodifications may be made, and therefore, the aim in the appended claimsis to cover all such changes and modifications.

The invention claimed is:
 1. A method, comprising: S1: establishingASM-mDON-DIN models for simultaneous simulation of microbial dissolvedorganic nitrogen (mDON) and inorganic nitrogen (DIN) in denitrificationprocesses; and S2: selecting a corresponding ASM-mDON-DIN modelaccording to a set carbon/nitrogen ratio to collaboratively optimizeconcentration values of mDON and DIN in an effluent of a denitrificationprocess, to obtain best process operation parameter values.
 2. Themethod of claim 1, wherein in S1, operations for establishing theASM-mDON-DIN models comprise: S1-1: data collection: measuring chemicaloxygen demand (COD), total nitrogen (TN), inorganic nitrogen (iDIN),dissolved organic nitrogen (rDON) and pH in an influent of a targetsewage plant in the denitrification process, inorganic nitrogen (eDIN)and dissolved organic nitrogen (eDON) in the effluent, dissolved oxygen(DO), a hydraulic retention time (t) of a denitrification stage, and amixed liquor suspended solid (MLSS) of activated sludge; S1-2: modelconstruction: according to a kinetic process of production,transformation and consumption of mDON during a complete denitrificationprocess, adding mDON as a new component and a carbon/nitrogen ratio as anew parameter into the ASM-mDON-DIN models, and constructingASM-mDON-DIN models 1 and 2 at different carbon/nitrogen ratios by usingmDON and DIN as objects; S1-3: model initialization: initializing theASM-mDON-DIN models based on data collected in S1-1, measured values ofmodel parameters and the ASM-mDON-DIN models constructed in S1-2; S1-4:model calibration: calibrating a parameter estimation function based onsimulated mDON and DIN kinetics and a result of sensitivity analysis;and S1-5: model establishment: replacing initial parameter values in theASM-mDON-DIN models with parameter calibration values to obtaincalibrated ASM-mDON-DIN models 1 and
 2. 3. The method of claim 1,wherein in S3, operations for selecting collaborative optimizationparameters comprise: S2-1: setting process parameter values: determiningset values of carbon/nitrogen ratio, pH and dissolved oxygen; S2-2:model selection: selecting the ASM-mDON-DIN model 1 or 2 according to anumerical value of the carbon/nitrogen ratio in S2-1; S2-3:collaborative optimization: based on the model selected in S2-2,obtaining a minimum value of a sum of a concentration of organicnitrogen and a concentration of inorganic nitrogen in the effluent andcorresponding process operation parameters by using the processparameter values set in S2-1 as a design factor of a response surfacemethodology and the sum of the concentration of organic nitrogen and theconcentration of inorganic nitrogen in the effluent as a response value;and S2-4: outputting best parameter values: outputting the minimum valueof the sum of the concentration of inorganic nitrogen and theconcentration of organic nitrogen in the effluent and the correspondingprocess operation parameters comprising the carbon/nitrogen ratio, pHand dissolved oxygen, obtained in S2-3.
 4. The method of claim 2,wherein the measured values of model parameters comprise initial valuesof a yield coefficient (Y_(H)) of anoxic growth of heterotrophicbacteria measured based on the data collected in S1-1, a proportion(f_(H,DON)) of mDON formed by heterotrophic bacteria based on organismgrowth, an ammoniated mDON half-saturation constant (K_(H,DON)) ofheterotrophic bacteria, a maximum specific growth rate (μ_(H)) ofheterotrophic bacteria and a nitrate half-saturation constant (K_(NO) ₃) of heterotrophic bacteria.
 5. The method of claim 2, wherein inorganicnitrogen component S_(DIN) comprises ammonia nitrogen, nitrate nitrogenand nitrite nitrogen.
 6. The method of claim 2, wherein the ASM-mDON-DINmodel 1 comprises 10 components, 8 processes, 22 parameters and akinetic parameter of an inhibition constant (K_(I4S) _(s) ) of theanoxic substrate of heterotrophic bacteria; and, the ASM-mDON-DIN model2 comprises 10 components, 8 processes and 22 parameters: 10 components:heterotrophic bacteria X_(H), particulate inert substance X_(I),dissolved biodegradable organic matter S_(S), microbial organic nitrogenS_(mDON), ammonia nitrogen S_(NH), nitrate nitrogen S_(NO3), nitritenitrogen S_(NO2), nitric oxide S_(NO), nitrous oxide S_(N2O) andalkalinity S_(ALK); 8 processes: four-step anoxic growth ofheterotrophic bacteria based on the dissolved biodegradable organicmatter, comprising conversion of nitrate nitrogen into nitrite nitrogen,conversion of nitrite nitrogen into nitric oxide, conversion of nitricoxide into nitrous oxide and conversion of nitrous oxide into nitrogen,and decay of heterotrophic bacteria, ammonification of microbialdissolved organic nitrogen, assimilative reduction of nitrate nitrogeninto nitrite nitrogen and assimilative reduction of nitrite nitrogeninto ammonia nitrogen; and 22 parameters: a yield coefficient Y_(H) ofanoxic Ss-based growth of heterotrophic bacteria, an oxygen containingproportion i_(XB) of organism, a proportion f_(H,DON) of mDON formed byheterotrophic bacteria based on organism growth, a proportion f_(I) ofinert substances produced by organism, a maximum specific growth rateμ_(H) of anoxic growth of heterotrophic bacteria, a half-saturationutilization constant K_(s) of a substrate of heterotrophic bacteria, anammonia half-saturation constant K_(H,NH) of heterotrophic bacteria, ananoxic growth factor η₂ of heterotrophic bacteria in a process 2, theanoxic growth factor η₃ of heterotrophic bacteria in a process 3, theanoxic growth factor η₄ of heterotrophic bacteria in a process 4, thenitrate nitrogen half-saturation constant K_(NO) ₃ , a nitrite nitrogenhalf-saturation constant K_(NO) ₂ , a nitric oxide half-saturationconstant K_(NO), a nitrous oxide half-saturation constant K_(N) ₂ _(O),a decay coefficient b_(H) of heterotrophic bacteria, an ammoniated mDONhalf-saturation constant K_(H,DON) of heterotrophic bacteria, anammonification rate κ_(α) of microbial dissolved organic nitrogen, a NO₃⁻—N half-saturation constant K_(7,NO3,) of ANRA, an inhibition constantK_(I7NH) of ammonia nitrogen in the ANRA process, an inhibition constantK_(I8NO2) of nitrite nitrogen in the ANRA process, a half-saturationconstant K_(8,NO2) of nitrite nitrogen in the ANRA process and an oxygenhalf-saturation constant K_(H,O) of heterotrophic bacteria.
 7. Themethod of claim 2, wherein the ASMN-mDON-DIN models 1 and 2 are dividedaccording to the carbon/nitrogen ratio in the influent: (1) when thecarbon/nitrogen ratio is less than or equal to 4, the model 1 isselected, and the kinetic equations for the model 1 are as follows:${{{DIN}\left( S_{DIN} \right)}:\frac{{dS}_{DIN}}{dt}} = {{\left( {{- i_{XB}} - \frac{f_{H,{DON}}}{Y_{H}}} \right)\left( {V_{1} + V_{2} + V_{3} + V_{4}} \right)} + V_{6} + \left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} +} \right.}$${\left. \frac{1}{0.571} \right)V_{2}};$${{{{mDON}\left( S_{mDON} \right)}:\frac{{dS}_{mDON}}{dt}} = {{\frac{f_{H,{DON}}}{Y_{H}}\left( {V_{1} + V_{2} + V_{3} + V_{4}} \right)} - V_{6}}};$${{{heterotrophic}{{bacteria}\left( X_{H} \right)}:\frac{{dX}_{H}}{dt}} = {V_{1} + V_{2} + V_{3} + V_{4} - V_{5}}};$${{{particulate}{inert}{{substance}\left( X_{I} \right)}:\frac{{dX}_{I}}{dt}} = {f_{I}V_{5}}};$${{dissolved}{biodegradable}{organic}{{matter}\left( S_{S} \right)}:\frac{{dS}_{s}}{dt}} = {{- \frac{1}{Y_{H}}}\left( {V_{1} + V_{2} + V_{3} +} \right.}$V₄) − 1.14V₇ − 3.43V₈;${{{nitric}{{oxide}\left( S_{NO} \right)}:\frac{{dS}_{NO}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{2}} + {\left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} + \frac{1}{0.571}} \right)V_{3}}}};$${{{nitrous}{{oxide}\left( S_{N2O} \right)}:\frac{{dS}_{N2O}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{3}} + {\left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} + \frac{1}{0.571}} \right)V_{4}}}};$${{{alkalinity}\left( S_{ALK} \right)}:\frac{{dS}_{ALK}}{dt}} = {{\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{1}} - \left( {\frac{i_{XB}}{14} + \frac{f_{H,{DON}}}{14Y_{H}} -} \right.}$${{\left. \frac{1 + {2.86f_{H,{DON}}} - Y_{H}}{14 \cdot \left( {0.571Y_{H}} \right)} \right)V_{2}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{3}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{4}} + {\frac{1}{14}V_{6}} + {\frac{1}{7}V_{8}}};$(2) when the carbon/nitrogen ratio is greater than 4, the model 2 isselected, and the kinetic equations for the model 2 are as follows:${{{DIN}\left( S_{DIN} \right)}:\frac{{dS}_{DIN}}{dt}} = {{\left( {{- i_{XB}} - \frac{f_{H,{DON}}}{Y_{H}}} \right)\left( {V_{1} + V_{2}^{\prime} + V_{3} + V_{4}^{\prime}} \right)} + V_{6} + \left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} +} \right.}$${\left. \frac{1}{0.571} \right)V_{2}^{\prime}};$${{{{mDON}\left( S_{mDON} \right)}:\frac{{dS}_{mDON}}{dt}} = {{\frac{f_{H,{DON}}}{Y_{H}}\left( {V_{1} + V_{2}^{\prime} + V_{3} + V_{4}^{\prime}} \right)} - V_{6}}};$${{{heterotrophic}{{bacteria}\left( X_{H} \right)}:\frac{{dX}_{H}}{dt}} = {V_{1} + V_{2}^{\prime} + V_{3} + V_{4}^{\prime} - V_{5}}};$${{{particulate}{inert}{{substance}\left( X_{I} \right)}:\frac{{dX}_{I}}{dt}} = {f_{I}V_{5}}};$${{dissolved}{biodegradable}{organic}{{matter}\left( S_{S} \right)}:\frac{{dS}_{s}}{dt}} = {{- \frac{1}{Y_{H}}}\left( {V_{1} + V_{2}^{\prime} + V_{3} +} \right.}$V₄^(′)) − 1.14V₇ − 3.43V₈;${{{nitric}{{oxide}\left( S_{NO} \right)}:\frac{{dS}_{NO}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{2}^{\prime}} + {\left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} + \frac{1}{0.571}} \right)V_{3}}}};$${{nitrous}{{oxide}\left( S_{N2O} \right)}:\frac{{dS}_{N2O}}{dt}} = {{\left( {\frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}} - \frac{1}{0.571}} \right)V_{3}} + \left( {{- \frac{1 + {2.86f_{H,{DON}}}}{0.571Y_{H}}} +} \right.}$${\left. \frac{1}{0.571} \right)V_{4}^{\prime}};$${{{alkalinity}\left( S_{ALK} \right)}:\frac{{dS}_{ALK}}{dt}} = {{\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{1}} - \left( {\frac{i_{XB}}{14} + \frac{f_{H,{DON}}}{14Y_{H}} -} \right.}$${\left. \frac{1 + {2.86f_{H,{DON}}} - Y_{H}}{14 \cdot \left( {0.571Y_{H}} \right)} \right)V_{2}^{\prime}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{3}} + {\left( {{- \frac{i_{XB}}{14}} - \frac{f_{H,{DON}}}{14Y_{H}}} \right)V_{4}^{\prime}} + {\frac{1}{14}V_{6}} + {\frac{1}{7}{V_{8}.}}$8. The method of claim 7, wherein the ASMN-mDON-DIN models 1 and 2comprise 8 process rate expressions respectively, which are V₁-V₈ andV₁′-V₈′: (1) anoxic growths (V₁ and V₁′) of heterotrophic bacteria basedon dissolved biodegradable organic matters (Ss) are:V ₁=μ_(H) ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO) ₃ (t)·M_(H,O)(t);V ₁ ′=V ₁; (2) anoxic growths (V₂ and V₂′) of heterotrophic bacteriabased on dissolved biodegradable organic matters are:V ₂=μ_(H)·η₂ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO) ₂ (t)·M_(H,O)(t);V ₂′=α·μ_(H)·η₂ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO) ₂(t)·M _(H,O)(t); (3) anoxic growths (V₃ and V₃′) of heterotrophicbacteria based on dissolved biodegradable organic matters are:V ₃=μ_(H)·η₃ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,NO)(t)·M_(H,O)(t);V ₃ ′=V ₃; (4) anoxic growths (V₄ and V₄′) of heterotrophic bacteriabased on dissolved biodegradable organic matters are:V ₄=μ_(H)·η₄ ·X _(H)(t)·M _(H,I,S) _(s) (t)·M _(H,NH)(t)·M _(H,N) ₂_(O)(t)·M _(H,O)(t);V ₄′=α·μ_(H)·η₄ ·X _(H)(t)·M _(H,S) _(s) (t)·M _(H,NH)(t)·M _(H,N) ₂_(O)(t)·M _(H,O)(t); (5) decays (V₅ and V_(s)′) of heterotrophicbacteria are:V ₅ =b _(H) ·M _(H,NO) ₃ (t)·X _(H)(t);V ₅ ′=V ₅; (6) ammonification (V₆ and V₆′) of microbial dissolvedorganic nitrogen is:V ₆=κ_(α) ·X _(H)(t)·M _(H,mDON)(t);V ₆ ′=V ₆; (7) assimilative reduction (V₇ and V₇′) of nitrate intonitrite is:V ₇=1.2·i _(XB) ·M _(ANRA,NO) ₃ (t)·M _(I,NH)(t)·M _(I7,NO) ₂ (t)(V ₁ +V₂ +V ₃ +V ₄ −V ₆);V ₇ ′=V ₇; (8) assimilative reduction (V₈ and V₈′) of nitrate intoammonia nitrogen is:V ₈=1.2·i _(XB) ·M _(ANRA,NO) ₂ (t)·M _(I,NH)(t)(V ₁ +V ₂ +V ₃ +V ₄ −V₆);V ₈ ′=V ₈; where M_(H,S) _(s) (t) is a Monod item of the substrate limitusing the dissolved biodegradable organic matters of heterotrophicbacteria; M_(H,I,S) _(s) (t) is an inhibition Monod item of thedissolved biodegradable organic matters of heterotrophic bacteria;M_(H,NH)(t) is a Monod item of the substrate limit using ammonianitrogen; M_(H,O)(t) is a Monod item of the oxygen limit ofheterotrophic bacteria; M_(H,NO) ₃ (t) is a Monod item of the nitratenitrogen limit; M_(H,NO) ₂ (t) is a Monod item of the nitrite nitrogenlimit; M_(H,NO)(t) is a Monod item of the nitric oxide limit; M_(H,N) ₂_(O)(t) is a Monod item of the nitrous oxide limit; M_(ANRA,NO) ₃ (t) isa Monod item of the nitrate nitrogen limit during the assimilativereduction of nitrate into nitrite nitrogen; M_(I,NH)(t) is an inhibitionMonod item of ammonia nitrogen during the assimilative reduction ofnitrate into nitrite nitrogen; M_(I7,NO) ₂ (t) is an inhibition Monoditem of nitrite during the assimilative reduction of nitrate intonitrite nitrogen; M_(ANRA,NO) ₂ (t) is a Monod item of the nitrite limitduring the assimilative reduction of nitrite nitrogen into ammonianitrogen; and, M_(H,mDON)(t) is a Monod item of the mDON limit producedby heterotrophic bacteria.
 9. The method of claim 2, wherein thesensitivity analysis uses an absolute-relative sensitivity equation tocalculate the influences of parameter changes on mDON and DIN.
 10. Themethod of claim 2, wherein the influent of the denitrification processin the target sewage plant satisfies the following conditions: 15°C.<environmental temperature<25° C., 2000 mg/L<sludge concentration<5000mg/L, 10 d<sludge age<30 d, 0<carbon/nitrogen ratio≤6.5, 6.5<pH≤8.5, and0≤dissolved oxygen≤0.5.